Benthic ecosystem functioning, anthropogenic impacts and climate change

The Witte group investigates the functioning of benthic marine ecosystems and benthic-pelagic coupling from the deep ocean floor to the intertidal, with a current focus on consequences of both anthropogenic activities and climate change.

This often includes the development of new research technologies, and one focus of ongoing work is the development of a pressurised coring, incubation and cultivation system for the study of biogeochemical processes and piezophile microorganisms from the deep seafloor under varying environmental conditions (pH, T, O2 etc.).

Sea ice is a unique feature of polar marine ecosystems and the fact that small temperature differences can have large effects on the extent and thickness of this sea ice makes polar marine ecosystems particularly sensitive to climate change. The group’s work on climate change impacts on benthic ecosystem functioning is therefore centred in the Canadian High Arctic where change is particularly rapid.

But we also work closer to home: Aberdeen is often referred to as the ‘oil capital of Europe’, and with hydrocarbon extraction now occurring down to 1100 m in the Faroe Shetland Channel, a need arises to understand the consequences of accidental releases in Scottish deep water environments in order to improve monitoring and optimize response measures after a spill. Several ongoing projects therefore investigate the rates and pathways of hydrocarbon degradation in Scottish Waters, as well as the microorganisms involved.

Benthic ecosystems such as deep water sponge grounds and cold water coral reefs are oasis of biodiversity, but particularly vulnerable to anthropogenic disturbance. Understanding the functional role of sponges in these unique ecosystems is another focus of our work.

In many cases, stable isotope tracing experiments, often carried out in situ at the deep-sea floor, help us track the pathway of organic matter, in particular C and N, through the benthic community and thus understand the spatial and temporal dynamics of biological and geochemical transformations of matter in benthic and benthopelagic food webs.

Current and recent projects

Current and recent projects from the Witte Group

  • Fate and flow of oil C in the marine food web - towards efficient monitoring of oil contamination. Application for NERC 2014-2018. PI Witte, with J. Anderson and E. Gontikaki.
  • ArcDeep: Arctic deep-sea ecosystem functioning in a changing climate.  NERC standard grant proposal; 2013-2016. PI Witte with F. Kuepper and P. Archambault (UoQuebec)
  • MAC-EXP: A pressurised coring, experimentation and cultivation system for deep-sea sedimentary ecosystems. NERC Technology-led standard grant 2013-2015. PI Witte with S. Chalmers.and J. Parkes (Cardiff)
  • The natural capacity for oil degradation of marine environments: towards developing DNA-based biosensors for monitoring low-level oil pollution. NERC, 2014-2015. PI U Witte,with J. Anderson and E. Gontikaki.
  • Planet Ocean - Streamlining the Marine Biodiscovery Pipeline (PharmaSea). EC FP7 2012-2016. PI: M Jaspers
Selected publications

Selected publications from the Witte Group

  • Enge AJ, Witte U , Kucera M, Heinz P. (2014)Response to a simulated phytodetritus pulse by benthic foraminifera in oxygen minimum zone sediments of the Western Indian margin. Biogeosciences 11, 2017-2016, 2014. Doi:10.5194/bg-11-2017-2014
  • Jobstvogt N, Hanley N, Hynes S, Kenter J & Witte U (2014). Twenty Thousand Sterling Under the Sea: Estimating the value of protecting deep-sea biodiversity. Ecological Economics 97 (2014) 10–19
  • Jeffreys RM,  Burke C,  Jamieson AJ, Narayanaswami BE,  Ruhl HA, Smith KLJr and Witte U (2013). Feeding preferences of abyssal macrofauna inferred from in situ pulse chase experiments. PLoS ONE 8(11): e80510. doi:10.1371/journal.pone.0080510
  • Gontikaki E, Thornton B, Huvenne VIA, Witte U (2013). Negative Priming Effect on Organic Matter Mineralisation in NE Atlantic Slope Sediments. PloS ONE 8(6): e67722. doi:10.1371/journal.pone.0067722
  • Levin LA, McGregor AL, Mendoza G, Woulds C, Cross P, Witte U, Gooday AJ, Kitazato H. (2013). Macrofaunal Colonization across the Indian Margin Oxygen Minimum Zone. Biogeosciences 10, 7161-7177, 2013. Doi:10.5194/bg-10-7161-2013
  • Serpetti N, Gontikaki E, Narayanaswamy  BE and Witte U. (2013) Macrofaunal community inside and outside of the Darwin Mounds Special Area of Conservation, NE Atlantic. Biogeosciences 10, 3705–3714, 2013; doi:10.5194/bg-10-3705-2013
  • Hunter W, Veuger B, Witte U (2012) Competition by metazoans and retention of labile organic matter regulate heterotrophic bacterial activity in oxygen minimum zone sediments. ISME Journal. 2012. 1-12.
  • Mayor DJ, Thornton B, Hay S, Zuur AF, Nichol WG, McWilliam JM, Witte U , (2012) Resource quality affects carbon cycling in deep-sea sediments. The ISME Journal (2012), 1–9
  • Zetsche EM, Bulling MT, Witte U  (2012) Permeability of intertidal sandflats: Impact of temporal variability on sediment metabolism. 2012  Cont. Shelf Research. DOI 10.1016/j.csr.2012.04.020
  • Moeseneder MM, K.L. Smith, Jr., H.A. Ruhl, D. Jones, U. Witte, and J. I. Prosser. Temporal and depth-related differences in procaryotic communities in abyssal sediments associated with particulate organic flux (2012). Deep-Sea Res I 70 (2012) 26-35.